The invention relates to rotary railroad car couplers, expecially rotary F-type couplers which employ vertically disposed cylindrical pins for attaching the butt end of the coupler shank to a rotary connector that acts as an intermediary member for rotatably fastening the coupler to the yoke of the rotary car coupler assembly which essentially includes the car coupler, striker, yoke, rotary connector and draft gear which are housed in the carsill that is attached to the underside of a railroad car.
There are non-rotary couplers of the E and F type, as described, for example, in U.S. Pat. No. 3,063,573, wherein a horizontal key is used to secure the butt end of the coupler shank directly to the yoke which is provided with a pair of horizontally aligned slots for receiving opposing ends of the key. All rotary F couplers use vertical pin attachments, if they employ pins for rotatably connecting the coupler to the yoke. The invention is directed to the adaptation of a horizontal key/slot connection of a non-rotating coupler to one that is rotatable.
Briefly stated, the invention is in a rotary railroad car coupler which employs a rotary connector for rotatably mounting the car coupler to the yoke. The rotary connector, when in a normal, unrotated operating position, has a pair of horizontally aligned slots that extend laterally from an opening which extends longitudinally through the connector and which is designed to receive the butt end of the coupler shank. The slots each have a generally oblong cross-section defined by two pairs of opposed surfaces which are convexly curved outwardly from the center axis of the slot and which are complimentary to the adjacent outer surfaces of a horizontal key which is used to fasten the coupler and connector together for unitary rotation. The key rests in the slots of the rotary connector and an aligned key slot which extends through the coupler shank adjacent the butt end.
The key slot of the coupler is horizontally disposed when the coupler is in a normal push/pull position, and is defined by a first pair of upper and lower surfaces which are configured and generally horizontally disposed to rockingly engage the adjacent curved surfaces of the key to increase vertical angling of the car coupler. The first pair of surfaces of the key slot of the coupler shank are connected by a second pair of opposed surfaces which are convexly curved outwardly from the center axis of the key slot and which are complimentary to the adjacent curved surfaces of the key to provide surface-to-surface bearing between the key and coupler shank, when the coupler is buff or pull, rather than the line-to-surface bearing between a cylindrical pin and a larger diameter pinhole.
The key has a pair of opposing ends which are cylindrically shaped and not spherical, as are the ends of the cylindrical pins presently used with rotary car couplers. The cylindrical end surfaces of the key provide better sliding contact and bearing against the adjacent cylindrical surfaces which form the cylindrical opening in the yoke.
As previously indicated, rotary railroad car coupler assemblies which utilize rotary connectors, employ cylindrical pins which are vertically disposed and have spherical ends. Such pins are maintained in position by a block that is secured within an opening in the yoke through which the pin is inserted into the aligned openings of the rotary connector and coupler shank. The jostling of the vertical pin and the retainer block during normal operation of the couplers in buff and pull, causes the block to wear in such a way that an offset develops between the worn block and adjacent yoke. This offset impedes the rotation of the coupler as the pin contacts the offset. The use of a horizontal key/slot arrangement, especially with a key having cylindrical and not spherical ends, eliminates this problem, since the horizontal key only contacts the retainer block upon rotation of the coupler 90.degree. from its normal operating position, and then such engagement is surface-to-surface contact which is less apt to form an undersirable groove in the block.